Acceleration responsive apparatus



April 29, 1969 R. L.. VANNATTER 3,441,594

ACCELERATION RESPONSIVE APPARATUS Filed Sept. 8, 1966 Seal 22 2J fea! 27 570/0 24 VIII,

m 'IIA' ///1 22 Marghe 34 15A@ A? fw United States Patent O 3,441,694 ACCELERATION RESPONSIVE APPARATUS Robert L. Vannatter, Ventura, Calif., assignor to General Dynamics Corporation, a corporation of Delaware Filed Sept. 8, 1966, Ser. No. 577,874 Int. Cl. Htllh 35/14, 35/38 U.S. Cl. 200-61.53 12 Claims This invention relates to acceleration responsive devices, and more particularly to acceleration sensitive mechanisms for activating a switch or the like upon a predetermined acceleration thereof.

vAcceleration responsive devices have been constructed in various manners and have been utilized for various purposes. U.S. Patents 2,713,097, 2,993,100 and 3,217,121 are exemplary of various prior art acceleration responsive devices. This type of apparatus are used especially for remote (in-Hight) activation and arming or -firing of components, particularly ordnance components of missiles, space vehicles, etc., such as fuze and warhead systems, self-destruct systems or propulsion systems.

The acceleration responsive apparatusof the present invention may be self-contained in a completely sealed enclosure or operated by the application or release of pressure through ports therein. It contains pressurized chambers, diaphragms or pistons, mass (g weights), appropriate valves and seals. The apparatus may be used to close electrical contacts, or displace, puncture, penetrate, detonate, etc., components requiring large forces with positive instantaneous action and continual high pressure contact.

Operation of the inventive apparatus is described and illustrated herein as an in-iiight safe and arming device using the inertial setback of a mass (g weight) by acceleration to establish pressure, air liow and time to effect switching and the closure of electrical contacts for the activation or firing of ordnance components. This apparatus is used to insure that a specified minimum acceleration is sustained over a period of time providing a safe distance from operating personnel, and then permitting the activation, arming or firing of ordnance components or other uses.

Therefore, it is an object of this invention to provide a new and improved acceleration responsive apparatus.

A further object of the invention is to provide means adapted to be utilized for operating a switch or other mechanism upon attainment of a desired velocity.

Another object of the invention is to provide an acceleration responsive device which embodies means for providing an amplified output motion in response to motion of another part thereof.

Another object of the invention is to provide a fluid pressure controlled timer and switching device.

Another object of the invention is to provide an apparatus using the inertial setback of a mass by acceleration to establish pressure, uid flow and time of effect switching and closure of electrical contacts.

Other objects of the invention will become readily apparent from the following description and accompanying drawings wherein:

FIG. 1 is a view partially in cross section illustrating an embodiment of the invention; and

FIGS. 2 and 3 are views partially in cross section showing modifications of the FIG. 1 embodiment.

Broadly, the present invention is directed to an acceleration responsive apparatus comprising a series arrangement of three pressure chambers, the first two of which operate under the inuence of an inertial mass actuating system to generate a pressure which, when applied to the third chamber, unseats a triggering inertial mass assembly to energize, for example, an electrical switch, In particular, when acceleration is applied to the system, the

first mentioned seismic mass assembly which comprises first and second mass elements is displaced so as to generate increased pressure in a reduced area of the first series chamber, there being a valve stem controlled by the two mass elements which blocks the said first series chamber from communication with the second. As one of the two mass elements bottoms against a stop in the first chamber, a pressure sufficient to unseat the triggering mass in the third chamber is developed. Upon additional acceleration, the second of the two masses in the first series chamber operates against a spring member to displace the valve stern, thus providing communication between the first and second chambers. The unseating pressure is then applied from the second series chamber to the triggering mass, unseating the same in a step fashion and actuating the electrical switch.

Referring now to FIG. 1, the acceleration responsive apparatus is enclosed in a housing generally indicated at 10 and having different cross-sectional portions 11 and 12, portion 11 -being smaller in cross-section than portion 12. Positioned in a threaded laperture 13 of the end of housing portion 11 is a threaded adjusting screw-like member 14 which functions to move a flexible member 15 for adjusting the area within that section of housing portion 11. Housing portion 11 is provided with partitions 16 and 17 having apertures 18 and 19, respectively, and which serve to define chambers or areas A1 and A2. In addition to the flexible member 15, which functions to adjust the area of chamber or area A1, this area is provided with a mass M1, electrical contacts 20, and leads 21 which extend through housing portion 11 and interconnect contacts 20 with the desired point of use. Seals 22 and 22 are located between the mass M1 and partition 16 and housing portion 11, respectively. Mass M1 includes a protruding flange portion 23 which functions to contact the contacts 20 when the mass M1 is moved as described hereinafter.

Housing portion 12 defines a chamber or are-a A3 while the section of housing portion 11 intermediate partiion 17 and housing portion 12 defines an area A3. Housing 10 includes a wall portion 24 which interconnects portions 11 and 12 and functions as a stop for mass M2 positioned within chamber or area A3. Mass M2 is provided with an aperture 25 through which extends a valve member 26. Seals 27 and 27 are respectively positioned within aperture 25 and at the periphery of mass M2. Valve member 26 is connected at one end with a mass M3 and is provided with a cut-away section 28 at the opposite end which extends into aperture 19 of partition 17. Seal means 29 is positioned in aperture 19 and is adapted to cooperate with the valve member 26 as the valve moves in response to acceleration. Valve member 26 is also provided with a cut-away section 3l) for the purpose described hereinafter. A sprirg 31 is operatively positioned intermediate masses M2 and M3.

Using hypothetical values, if the area A1 is charged with a pressure P1 of 50 pounds and the pressure is applied to the full surface area S1 of mass M1, a force equal to (SOXSI) is applied to maintain M1 seated against seal 22.

Wilh the areas A2, A3, and A3' charged to an equal pressure P2, P3 and P3 of 25 pounds, due to the cutaway section 23 of valve 26, and this pressure is applied to only half the surface area ('1/2S2) of M1 the force in that direction is equal to (25X1/2S2) or 1A the force of P1 applied against surface S1 of mass M1.

The pressure P2 required to displace mass M1 is greater than pounds, 100 pounds being the threshold value (l0O 1/2S2)=(50 S1). M1 is thus maintained in the deactivated position until P2 reaches a value of 100 pounds. This is accomplished when the desired value of acceleration, indicated by the arrow at 32 is sustained for the required period of time, for example, gs for 2 seconds. When acceleration starts (any suitable value such as between 1 and 8 gs) masses M2 and M3 and the spring 31 will be set back toward the stop 24 in anticipation of the attainment of 10 gs. The fluid, such as air, in the areas A3 and A3 is compressed into the area A3 due to valve 26 filling the aperture 19 in partition 17 when mass M3 moved to the right. The pressure P3 thus increases to a value which, when the fiuid is allowed to flow into the area A2, will cause a pressure P2 greater than 100 pounds.

When masses M2 and M3 are set back toward the stop 24 the valve 26 between areas A2 and A3 becomes closed and will remain closed until the acceleration returns to zero or when a value of 10 gs is reached. Upon reaching 10 gs the mass M3 is further set back against the spring 31 to the point where the valve 26 becomes open due to the cut-away section 30 thereof entering aperture 19 in partition 17. At this instant the fluidstarts to flow from the highly pressurized area A3 into area A2. The amount of fiuid flow is determined by the pressure differential of P3', P2 and the size of the valve opening. At the end of the prescribed time the air flowing into A2 will have caused the pressure P2 to reach the threshold value of 100 pounds. Any further increase in pressure will cause the mass M1 to start to be displaced. As soon as M1 moves away from the seal 22 the full surface area S2 of mass M1 is exposed to this 100 pounds pressure and the force in that direction increases in a step function to twice the value. Mass M1 is immediately displaced in a rapid switching action, wherein flange portion 23 thereof closes the electrical contacts and maintains them closed under high pressure.

As pointed out above, the inventive apparatus may be self contained as described above or operated by the application or release of fiuid pressure through ports in the housing 10.

Referring now to FIG. 2, housing portion 11 is modified at 33 so as to support a permanent magnet 34 while a coil 35 is Wrapped -around mass M1. In FIG. 3, the mass M1 is of magnetic material and housing portion 11 is modified to include a projection 36 which supports a coil 37. Thus, if the mass M1 contains an electrical coil surrounded by a permanent magnet (FIG. 2), or if M1 is a magnet surrounded by a coil (FIG. 3), or otherwise located to produce relative motion between the coil and magnetic field when M1 is displaced, an electrical impulse will be generated in the coil of sufficient energy to activate or trigger other electrical devices or to detonate ordnance components such as explosive elements, squibs, igniters, etc. The relative motion between the magnetic field and coil at the high rate produced by the rapid displacement of M1 provides the apparatus with the capability of supplying its own self generated electrical energy. In addition, this electrical energy is generated precisely, and only, at the time it is to be used, thus providing a good safety factor.

It has thus been shown that this invention provides an acceleration responsive apparatus that insures that a specified minimum acceleration is sustained over a period of time providing a safe distance from operating personnel, and then permitting the activation, arming or firing of ordnance components or other desired use.

While particular embodiments have been illustrated and described, modifications will become apparent to those skilled in the art, and it is intended to cover in the appended claims all such modifications as come within the true spirit and scope of the invention.

What I claim is:

1. An acceleration responsive apparatus comprising a housing having partitions with apertures therein to provide a series arrangement of first, second, and third pressure chambers, an inertial mass actuating system reactive within said first pressure chamber, a triggering inertial mass assembly seated within said third pressure chamber,

said inertial mass actuating system under the influence of the acceleration generates a pressure which, when applied to said third pressure chamber unseats said triggering inertial mass assembly; said inertial mass actuating system including first and second mass elements, a valving member operatively connected to one of said mass elements and which, under certain conditions, blocks said first pressure chamber from communication with said second pressure chamber, said valving member being provided with means which provide communication between said first and second series pressure chambers by moving through one of said apertures under predetermined conditions of acceleration, and resilient means operatively interconnecting said first and second mass elements; said first pressure chamber being provided with stop means for said inertial mass actuating system, whereby upon a predetermined acceleration one of said first and second mass elements bottoms against said stop means and said valving member is moved through one of said apertures so as to block communication between said first and second pressure chambers allowing a pressure sufiicient to unseat said triggering mass assembly to develop in said first pressure chamber, and whereby upon predetermined additional acceleration, the other of said first and second mass elements moves against said resilient means and said valving member is moved so as to provide communication between said first and second pressure chambers providing in said second pressure chamber and against said triggering mass assembly a pressure sufficient to move said triggering mass assembly against the pressure in said third pressure chamber, said triggering mass assembly being moved in a step fashion thus causing a rapid displacement thereof and maintaining of said triggering mass assembly in the actuated position until acceleration has been reduced below a predetermined amount.

2. The acceleration responsive apparatus defined in claim 1, wherein said second mass element of said inertial mass actuating system is connected to said valving member.

3. The acceleration responsive apparatus defined in claim 1, wherein 4said valving member is a longitudinally disposed element and said means thereon for providing communication between said first and second series pressure chambers comprises a cut-away section at the one end thereof adjacent said second pressure chamber and another cut-away section positioned at a predetermined distance from said one end.

4. The acceleration responsive apparatus defined in claim 1, wherein said second and third pressure chamber have substantially the same cross-sectionally configuration, and wherein said first pressure chamber has a portion of substantially the same cross-sectionally configuration as said second and third pressure chambers and a portion having a larger cross-section.

5. The acceleration responsive apparatus defined in claim 4, wherein said stop means is defined by a portion of said housing intermediate said different cross-sectional portions of said first pressure chamber.

6. The acceleration responsive apparatus defined in claim 1, wherein said first mass element of said inertial mass actuating system is provided with a central aperture within which said valving member is adapted to move, and seal means positioned in said aperture and at the periphery of the element.

7. The acceleration responsive apparatus defined in claim 1, additionally including seal means positioned in said aperture of said partition intermediate said first and second pressure chambers, and adapted to cooperate with said valving member.

8. The acceleration responsive apparatus defined in claim 1, wherein said aperture of said partition intermediate said second and third pressure chambers has an area approximately one-half the area of the triggering inertial mass assembly surface adjacent said partition.

9. The acceleration responsive apparatus defined in claim 1, additionally including seal means intermediate said triggering inertial mass assembly and said partition intermediate said second and third pressure chambers and adjacent the periphery of said aperture in said partition.

10. The acceleration responsive apparatus defined in claim 1, additionally including seal means at the periphery of said triggering inertial mass assembly.

11. The acceleration responsive apparatus defined in claim 1, additionally including means for adjusting the area of said third pressure chamber,

12. The acceleration responsive apparatus dened in claim 1, additionally including electrical contact means operatively positioned in said third pressure chamber for connection with a point of use, said contact means being activated by movement of said triggering inertial mass assembly.

References Cited UNITED STATES PATENTS 2,713,097 7/1955 Wooten 200e-61.53

ROBERT K. SCHAEFER, Primary Examiner.

MORRIS GINSBURG, Assistant Examiner. 

1. AN ACCELERATION RESPONSIVE APPARATUS COMPRISING A HOUSING HAVING PARTITIONS WITH APERTURES THEREIN TO PROVIDE A SERIES ARRANGEMENT OF FIRST, SECOND, AND THIRD PRESSURE CHAMBERS, AN INERTIAL MASS ACTUATING SYSTEM REACTIVE WITHIN SAID FIRST PRESSURE CHAMBER, A TRIGGERING INERTIAL MASS ASSEMBLY SEATED WITHIN SAID THIRD PRESSURE CHAMBER, SAID INERTIAL MASS ACTUATING SYSTEM UNDER THE INFLUENCE OF THE ACCELERATION GENERATES A PRESSURE WHICH, WHEN APPLIED TO SAID THIRD PRESSURE CHAMBER UNSEATS SAID TRIGGERING INERTIAL MASS ASSEMBLY; SAID INERTIAL MASS ACTUATING SYSTEM INCLUDING FIRST AND SECOND ELEMENTS, A VALVING MEMBER OPERATIVELY CONNECTED TO ONE OF SAID MASS ELEMENTS AND WHICH, UNDER CERTAIN CONDITIONS, BLOCKS SAID FIRST PRESSURE CHAMBER FROM COMMUNICATION WITH SAID SECOND PRESSURE CHAMBER, SAID VALVING MEMBER BEING PROVIDED WITH MEANS WHICH PROVIDE COMMUNICATION BETWEEN SAID FIRST AND SECOND SERIES PRESSURE CHAMBERS BY MOVING THROUGH ONE OF SAID APERTURES UNDER PREDETERMINED CONDITIONS OF ACCELERATION, AND RESILIENT MEANS OPERATIVELY INTERCONNECTING SAID FIRST AND SECOND MASS ELEMENTS; SAID FIRST PRESSURE CHAMBER BEING PROVIDED WITH STOP MEANS FOR SAID INERTIAL 